Chemical Waste Management and Disposal
Chemical Waste Management and Disposal
Waste Management
- Nonhazardous waste
• General guidelines- Storage - Packaging
• Special categories- – Metal waste
- – Radioactive and mixed waste
- – Biological waste
- – Unknown and orphan waste
- Treat on-site
Waste management: nonhazardous waste
- Used oil (uncontaminated) is not considered hazardous
waste. Label Containers "USED OIL", not "hazardous waste."
- Uncontaminated PPE (gloves, wipes)
- Triply rinsed glassware (bottles, droppers, pipettes)
- Salts (KCl, NaCl, Na CO )
2
3
- Sugars - Amino acids
- Inert materials (uncontaminated resins and gels)
Waste management: General guidelines
- Secure and lock waste storage area
- Post signs to warn others
- Keep area well ventilated
- Provide fire extinguishers and alarms, spill kits
- Provide suitable PPE
- Provide eye wash, safety showers
- Do not work alone
Waste management: General guidelines
- Insure against leakage; dyke area
if possible
- Label all chemicals, containers,
vials
- Separate incompatible chemicals
- Keep gas cylinders separate
- Keep radioactive material separate
- Know how long waste can be
stored
- Provide for timely pick-up
Waste - Storage guidance
- Container should not react with the waste
being stored (e.g. no hydrofluoric acid in glass).
- Similar wastes may be mixed if they are
compatible wastes from
- Whenever possible,
incompatible hazard classes should not be mixed (e.g. organic solvents with oxidizers).
- Containers must be kept closed except
during actual transfers. Do not leave a funnel in a hazardous waste container.
- Chemical containers that have been triple-
rinsed and air-dried in a ventilated area can be placed in the trash or recycled.
Waste – General guidance Certain metals cause disposal problems when mixed with flammable liquids or other organic liquids Pressure can build up in a waste vessel Corrosion can occur in storage vessel Secondary containment is necessary Glass waste containers can break
Dangerous waste management
Video – Fire at Apex Waste Facility
Best practice – Orphan control
Before moving to new job meet with new lab occupant
- This can be a new employee or new student
- Label all chemicals and samples carefully
- Make notations in common lab book
Dispose of all unneeded or excess chemicals
- Put into chemical exchange program
- Dispose of as hazardous waste
Do not leave any chemicals behind except by agreement
Waste management
- Recycle, reuse, redistill, if possible
- Dispose by incineration, if possible
- Incineration is NOT the same as open burning
Emissions from incineration vs. open burning Open Municipal Burn Waste Incinerator (µg/kg) (µg/kg) PCDDs 38 0.002 PCDFs 6 0.002 Chlorobenzenes 424150
1.2 PAHs 66035
17 VOCs 4277500
1.2 Source: EPA/600/SR-97/134 March 1998
Lab packs consists of small containers of compatible waste, packed in absorbent materials. Lab packs segregated at hazardous waste facility Laboratory wastes are packaged in small containers
Waste management: Waste disposal service
- Is disposal service
licensed?
- How will waste be
transported?
- How will waste be
packaged?
- Where will material be
disposed?
- How will it be disposed?
- Maintain written records
Battery recycling and disposal Hazardous waste
- Lead acid (Pb) - recycle (90% car batteries)
- Sealed lead (Pb) - recycle
- Mercury-oxide (HgO) button, silver-oxide
(AgO) button - recycled by jewelers
- Nickel Cadmium (NiCd) recycle
Nonhazardous waste
- Nickel Metal Hydride (Ni-MH) recycle
- Carbon – zinc
- Alkaline • Zinc-air button
Mercury metal disposal
- Collect pure liquid mercury in a sealable
container. Label as "MERCURY FOR RECLAMATION"
- Place broken thermometers and mercury
debris in a sturdy sealable plastic bag, plastic or glass jar. Label the container "Hazardous Waste - MERCURY SPILL DEBRIS" .
- Never use a regular vacuum to clean up a
mercury spill - contaminates vacuum, heat evaporates the mercury
- Never use a broom to clean up mercury –
spreads smaller beads - contaminates the broom.
Mixed Waste (chemical radioactive) These wastes must be minimized - heavily regulated Universities, hospitals Low level radioactive with chemical Scintillation cocktails Gel electrophoresis waste Nuclear energy research Low and high level radioactive with chemical Lead contaminated with radioactivity
Mixed Waste (chemical-biological)
- Medical wastes
- – Blood and tissue
- – Sharps – needles, scalpels
- – Contaminated glassware, ppe
- Autoclave or sterilize
- – Bleach incompatible with autoclave
- – Do not autoclave flammable liquids
- Incinerate
Mixed Waste (radioactive-biological) Medical wastes
- – Often disinfect high biohazard
to minimize handling risk
- – Let short-lived isotopes decay
and then use sanitary sewer
- – Refrigerated storage for
putrescible waste (carcasses- tissue)
- – Autoclave or disinfect labware
and treat as low level radioactive
- – On-site incineration of low
level rad waste if permitted (sharps as well)
Unknown “orphan” waste
Avoid if at all possible -- requires analysis before disposal!
Pre-screen Crystals present ? (potential peroxide formation) Radioactive (Geiger counter) Bio waste? (interview history) Screen Prepare for the worst – wear gloves-goggles-hood Air reactivity Water reactivity Flammability CorrosivityUnknown waste characterization* Physical description - Water reactivity - Water solubility pH and neutralization information Presence of:
Oxidizer Sulfides or cyanides Halogens Radioactive materials Biohazards Toxics
*Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy
Press, 1995 Section 7.B.1
Waste management: Down the drain? If legally allowed:
- Deactivate & neutralize some
liquid wastes yourself
- – e.g., acids & bases
- – Don’t corrode drain pipes
- Dilute with lots of water while
pouring down the drain
- Be sure that you do not form
more hazardous substances
- – Check reference books,
scientific literature, internet
Treating on site – volume reduction Evaporation – if not excessive
- Roto evaporation for recovery
- Do not evaporate corrosives or
radioactives
- Only in laboratory hood
- Beware toxics and flammables
Adsorption
- Activated carbon
- Ion exchange resin
- Activated alumina
Precipitation - Extraction Handbook of Laboratory Waste Disposal, Martin Pitt and Eva Pitt, 1986. ISBN 0-85312-634-8
Treating on site – chemical conversion Requires chemical expertise - may not be allowed by regulations - specific to each chemical Dilution to reduce hazard
- H O , HClO , HNO
2
2
4
3
- Never add water to concentrated acid
- Neutralization acid base -gentle
Hydrolysis (acid and base)
- Active halogen compounds with NaOH
- Carboxamides with HCl
Oxidation-reduction Handbook of Laboratory Waste Disposal, Martin Pitt and Eva Pitt, 1986. ISBN 0-85312-634-8
Chemical Waste Example: Tollens Reagent Ag(NH ) NO (aq)
3
2
3
- The reagent should be freshly prepared and stored
refrigerated in a dark glass container. It has a shelf- life of ~24 hours when stored in this way.
- After the test has been performed, the resulting
mixture should be acidified with dilute acid before disposal. These precautions are to prevent the formation of the highly explosive silver nitride.
Waste management: Treatment in Lab
- References:
- – “Procedures for the Laboratory-Scale Treatment of
Surplus and Waste Chemicals, Section 7.D in Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy Press, 1995, available online:
– “Destruction of Hazardous Chemicals in the Laboratory,
nd
2 Edition”, George Lunn and Eric B. Sansone, Wiley Interscience, 1994, ISBN 978-0471573999.
– “Hazardous Laboratory Chemicals Disposal Guide, Third
Edition”, Margaret-Ann Armour, CRC Press, ISBN 978- 1566705677
- – “Handbook of Laboratory Waste Disposal”, Martin Pitt
and Eva Pitt, 1986. ISBN 0-85312-634-8
On-site Recycling and Waste Treatment
Waste Management: Recycling Recycling by redistribution Recycling of metals Gold-mercury–lead- silver Recycling of solvents Clean for reuse-rotovap Distill for purity Recycling of oil Recycling of E-waste
Chemical recycling
Reuse by others in the organization or community
An active chemical exchange program Beware of accepting unusable chemicals Reuse in experiments in the laboratory Exchange for credit with suppliers by agreementWhat should not be recycled
- Gas cylinders past their pressure testing date
- Used disposable pipettes and syringes
- Chemicals and assay kits past their expiration
- Obviously degraded chemicals
- Used tubing, gloves and wipes
- Others?
What should be recycled or redistributed?
- Excess unopened chemicals
- Excess laboratory glassware (unused or clean)
- Consumables with no expiration
- Solvent that can be purified>Lower purity suitable for secondary use?
- Precious or toxic metals
- Hg, Ag, Pt, Pd, Au, Os, Ir, Rh, Ru • Others?
Chemical Recycling - Precious Metal For reuse in lab or for exchange
- Requires chemical knowledge for lab reuse
- Recover from solution - evaporate then
- Ignite (Au, Pd, Pt)
for metal powder or
- Reduce with NaBH
4 by electroless plating (Pt, Au, Pd, Ag, Rh).
- Electroplate • Metal recovery Ion exchange-then ash
Source : Handbook of Laboratory Waste Disposal, Pitt &Pitt, John Wiley, 1986
Chemical Recycling - Silver Recovery from chemical oxygen demand (COD) test
- Acidification and ppt as AgCl
Recovery from photographic fixing solution
- Precipitate as sulfide
- Precipitate with TMT (trimercapto-s-
triazine)
- Electrolysis (terminal and in-line)
- Metal replacement (iron containing
cartridges)
- Ion exchange
Many companies will buy the recovered
Chemical Recycling - Mercury
- Mercury can be recovered for
subsequent lab use or for recycle by vendor
- Remove particulates and moisture
by allowing slow drip through a hole in a conical filter paper
- Never distill Hg on-site
Solvents can be recovered by distillation
- Boiling point must be widely
different
- Azeotropes may prevent
separation
- Sometimes hazards are created
- Some solvents do not need
complete separation
- Hardware for separation
Solvent recycling – general guidance Solvent recycling requires care and organization
- Keep solvents segregated
prior to separation (single product solvent)
- No unnecessary dirt due to
careless handling
- Requires good labeling
- A small amount of the wrong
chemical can ruin a desired separation
- Care must be taken not to
concentrate peroxides
Solvent recycling – general guidance Solvent recycling requires care and organization
- Try other purification methods before
distillation
- Convert to precipitate
- Convert to water soluble
- Use an adsorbent>Need BP difference of > 10°C
- Can form azeotrope*>water / ethanol (100°C/ 78.3°C)
- cyclohexane / isobutanol (81°C / 108°C)
- Mixture of 4 solvents not practical
- Distillation can be incorporated into
curriculum * Consult CRC Handbook of Chemistry and Physics for list of azeotropes
Solvent recycling – low efficiency Rotovap can be used to pretreat
- Toxic material may be kept
from the distillation
- May be sufficient if purity is
not crucial
- Separation of solvent from
solids
Solvent recycling – basics
Reflux ratio TP 120
25 Reflux
80
24 Distillate
40
21
20
16
10
10
4
leads to increased separation efficiency TP = theoretical plates
Solvent recycling – medium efficiency
- Even high efficiency stills are not
Example: 200mm long perfect
column for separating
- Continuous better than batch for
benzene and toluene large volumes
- Control reflux
Packing TP
- Monitor head temperature
Empty
0.5
- Reduce heat loss to get more
efficiency Coarse packing
1
- Do not let still operate to dryness
Fine packing
5
- Use boiling chips but do not add
when solvent is hot
TP = theoretical plates
Diagram of packed and spinning band
distillation columns
Diagrams from B/R Instruments: http://www.brinstrument.com/Boiling point of common solvents (C) Halogen Containing
CH Cl Dichloromethane
40 2 2 CH Cl Chloroform
61.6 3 CCl Carbontetrachloride
76.5 4 C H Cl Trichloroethane
87 2 3 3 C Cl Perchloroethylene or Tetrachloroethylene 121 2 4 C HCl
Trichloroethylene
87 2 3 C H Cl Trichlorobenzene (TCB)
208.5 6 3 3
Boiling point of common solvents (C) Oxygen Containing
C H O Acetone
56.1 3 6 C H O MEK (Methyl ethyl ketone)
79.6 4 8 C H O Acetic acid
118.1 2 4 2 C H O Ethyl acetate
77 4 8 2 C H O Ethylene glycol 197 2 6 2 C H O
Propylene glycol 187 3 8 2 C H O Ethyl ether
34.5 4 10 C H O THF (tetrahydrofuran)
66 4 8 C H O MIBK (Methyl isobutyl ketone) 116.8 6 12
Boiling point of common solvents (C)
Oxygen Containing (cont)
CH O Methanol
64.5 4 C H O Ethanol
78.3 2 6 C H O n-Propanol
97 3 8 C H O Isopropanol
82.5 3 8 C H O n-Butanol 117.2 4 10 C H O sec-Butanol
99.5 4 10
Boiling point of common solvents (°C) Hydrocarbons
C H n-Pentane
36.1 5 12 C H n-Hexane
68.7 6 14 C H Cyclohexane
80.7 6 12 C H n-Heptane
98.4 7 16 C H n-Octane/iso-octane 125.7 / 117.7 8 18 C H Toluene
110 7 8 C H Ethylbenzene 136.2 8 10 C H p/m/o-Xylene 138.3 / 139.1 / 144.4 8 10
Boiling point of common solvents (C) Nitrogen Containing
C H N Pyridine 115 5 5 C H N
Aniline 184 6 7 C H NO n,n-Dimethylformamide 149-156 3 7 C H NO n-Methylpyrolidone
202 5 9 C H N Piperdine
106 5 11 C H N Acetonitrile
81.6 2 3
Solvents that should not be recycled by distillation
Accidents have been reported for these distillations
Individual Substances
- Di-isopropyl ether (isopropyl alcohol)
- Nitromethane • Tetrahydrofuran • Vinylidene chloride (1,1 dichloroethylene)
Mixtures
- Chloroform + acetone
- Any ether + any ketone
- Isopropyl alcohol + any ketone
- Any nitro compound + any amine
Practical examples of recycling
- Hexane contaminated with small amount of
inert solvent used in prep lab
- Chemistry students given a finite quantity of
solvent, then had to recycle for subsequent experiments • Acetone 50% in water for washing. Azeotrope is 88.5% which is then diluted back with water for reuse
- Use rotovap recovery rather than
evaporation. Student will redistill; 60% recovery.
- Third wash was captured and used as first
wash on next experiment Source : Handbook of Laboratory Waste Disposal, 1986.
Marion Pitt and Eva Pitt, John Wiley and Sons, ISBN 85312-634-8
Solvent recycling Automated systems help with large needs
HPLC Solvent Recycling GPC Solvent Recycling Environmental Laboratory Solvent Recycling Freon Solvent Recycling Histology Laboratory Solvent Recycling General Lab Solvent Recycling Services Can also be Purchased
Pictures from B/R Instruments: http://www.brinstrument.com/
Any Questions?